The amour fou between the great photographer Lartigue and his enigmatic model, Renee Perle, produced the finest female portraits of his life. By Robin Muir
At the age of seven, the photographer Jacques-Henri Lartigue was given his first camera - an unwieldy affair with a wooden tripod, large, greenish-yellow plates and a lens-extension of pleated cloth. It would appear spectacularly unsuitable for a child, but the year was 1901 and photography was only decades old. Some of the cameras in his father's collection, he wrote, were "enormous - like ogres!". Few since then have articulated the bewitching nature of the medium with such instinctive spontaneity: "Now I will be able to make portraits of everything... everything!," he confided in his journal. "I know very well that many, many things are going to ask me to have their pictures taken, and I will take them all."

In his 92 years, he went on to produce at least 275,000 images in 116 albums, dated, captioned and organised, as one commentator noted, "as one would a herbarium". He bequeathed them all to the French state, and, since his death in 1986, L'Association de Jacques-Henri Lartigue has administered them.

Vintage material by Lartigue rarely comes on the market, but on 2 May, in London, Sotheby's is offering for sale a remarkable group of 21 prints. They document a love affair over two summers in the South of France between the photographer and his girlfriend Renee Perle, and have been consigned by her descendants. Though the affair was brief, she must have asked for - or been given - these pictures as a memento of their time together.

Lartigue left an account of their first meeting in his book Diary of a Century, published nearly 40 years later: "Along the sidewalk of the Rue de la Pompe, I see two women standing in the shadow of a street lamp. Are they waiting for someone or... something? One of the women is tall and slender, the other is tiny. An umbrella next to a pot of flowers. Later, in the Bois, the umbrella is in my car between the flowers and me. I look at her profile. A long neck; a very straight, very small nose. A shiny, stray hair lock caresses her mouth. She has gloves on... I wish I could see her hands. Hands are so important!"

Wondering aloud if she might have been Mexican, he received the reply, "Romanian - my name is Renee Perle. I used to be a model at Doeillet."

By the time they met, Lartigue had separated from his wife Bibi, daughter of the composer Andre Messager, and he launched himself into the new affair. The photographic evidence of their liaison, mostly conducted at Biarritz and Juan-les Pins, is as magical as anything Lartigue might have wished for as a seven-year-old with a plate camera. They are among his finest pictures, certainly the best of his many portraits of women.

It is easy to see how the exotic Renee beguiled him. Even behind the grubby windscreen of an open-topped car, wearing motoring goggles with a nose-guard and a net to protect her hair from the wind, she possesses an insouciant charm.The captions to this part of Diary of a Century are unashamedly lyrical: "Her mouth against mine, long bare legs, hair against my cheek - and that scent!"

Their affair was as passionate as it was tender: "She is always making scenes," he wrote. "Is it jealousy, or is it madness? Maybe it is the need to be assaulted, to be made unhappy and to cry - all for the sake of a reconciliation? I am far too down-to-earth, too much of a spectator and too bad an actor to fall into the trap of playing the kind of game Renee wishes me to play."

After the affair was over in 1932, Lartigue turned to the moving image and to illustrating fashion magazines. He took up photography again, in a haphazard way, in the 1950s. His family wealth allowed him to never have to work, and it is perhaps the knowledge that he had to take pictures for no one but himself that lends them such distinctive charm.

And what became of Renee Perle - "around whom I always see a halo of magic"? Little more is known about her once the second summer ended. She married, had children, grew old, we presume, and died leaving behind only these pristine souvenirs from more than half a century ago - though the purchaser of the photograph Renee with Necklace can also buy the necklace itself, a knotted string of silvered metal discs and large, pearlised beads. Her family, who have put the prints up for sale, cannot be contacted.

"Certain insects die after having made love," Lartigue wrote, "but they make love anyway. Every second of the present counts. I will think about the future later... But there is one haunting thought: with whom can I expect to talk about love after Renee has gone?"

Jacques-Henri Lartigue's portraits of Renee Perle are included in Sotheby's photographic sale, New Bond Street, London on 2 May at 2.30pm